Transmitter for etheric ir wireless telephone systems.



F. H. MTLLENER.

TRANSMITTER FOR ETHEHIC 0R WIRELESS TELEPH GNE SYSTEMS.

APPITICATTON FILED NOV. 1. 1912.

Patentd 0m. 3,1916.

2 SHEETS-:SHEET 1.

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v as kggx uq F. H. MILLENER.

APPLICATION FILED NOV. 7. 191

' Patented OctS, 1916 2 SHTIETS-S-HEET 2.

TTnm-wgmum 79 in s FREDERICK HOYER MILLENER, or OMAHA, ituenhske.

' TRANSMITTER FOR ETHERIC OR WIRELESS TELEPHON E SYSTEMS.

Specification of Letters Patent.

enema Got. a, 1916.

Application filed November 7, 1912. Serial No. 730,623.

phone system, and is designed more particupowerful reproduction at thereceiving station.

To this end the apparatus is constructed as shown in the accompanyingdrawings, representing a typical embodiment of the invention, wherein:

Figure 1 is a perspective elevation show-- ing both the transmitting andreceiving apparatus mounted upon a common board or support, thetransmitter being on, the righthand half; Fig. 2 is a section on theline 22 of Fig. 1; Fig. 3 is a detail view of the microphone button,supporting'bridge, etc.,

within the transmitter; and Fig. 4; is a diagrammatic illustration ofthe electrical connections.

In these drawings 1 indicates a board or support, upon which are mountedthe transmitting apparatus A and the receiving apparatus B, with suchother special devices as may be deemed convenient or necessary.

To the board or support 1 is secured an insulating slab or plate 2, towhich are applied insulating binding posts 3, 4, 5 and 6. \7 indicatesthe usual bracket-arm or su port, such as is commonly employed for t eordinary Bell telephone transmitter, and 8 the arm hinged or pivoted tosaid bracket, and serving to support the transmitter.

Formed with, or secured to the free or outer end of said arm 8 by screwsor other suitable fastenings, is a head or block 9, conveniently made ofcircular form, and having a. series of holes or openings 10 equallyspaced about its axis, and extending obliquel to said axis through theblock or head i rom casing one face to the other, as well illustrated inFig. 2. These several openings are all at common angle to the axis ofthe block or head 9', and to the axis of the megaphone horn 11 andmouthpiece 12 carried thereby. Each of the holes or openings 10 in thehead or block 9 is enlarged to receive one end of a tube 13, theopposite end of which. carries a shell or casing 14 having the usualtelephonic transmitter, preferably of the type or construction set forthin Letters Patent No. 485,311 to A. C. White, dated Novem her 1, 1892.This specific construction is not essential to the present invention,and is merely noted as illustrating one of'many forms of microphonictransmitter suitable for use in this connection. The tubes 13 may besoldered, screwed, or otherwise made fast in the head 9, and should beas nearly alike as possible in all dimensions-length, diameter,thickness, and also in kind and quality of metal, alloy or material.They should be equally spaced, and bear like relation to the megaphone11 and its mouthpiece 12, and their interior surfaces should formcontinuations of the openings 10 through the head 9 without shoulder orbreak, and the inner surfaces of the tubes 13 and openings 10 as also ofthe megaphone, should be very smooth or highly polished.

The shells 14 each comprise an annular base 15, screwed or otherwisesecured to the tubes 13, and a dome-shaped cap or cover 16. Withinthe'chamber inclosed by said base and cap is arranged the diaphragm 17,with which the microphone button 18 is mechanically connected, saidbutton being carried as usual by a bridge-piece 19 in electrical contactwith the base 15, andthrough the latter with the tubes 13, head 9,supporting arm 8 and bracket 7. An insulating thimble or socket-piece 20passing through the cap 16, and supported upon the bridge-piece 19,carries and insulates a conducting thimble 21, which receives the end orterminal of a conducting wire 22. The thimble 21 is in turn electricallyconnected with the microphone button 18, or the movable member thereof,by a Wire or conductor 23, as shown in Fig. 3. In other words, theconstruction and arrangement of parts in the shell or 14: are as usualin transmitters of the type lndicated.

From the binding screw 4 a conducting wire 24 passes to and iselectrically connected with the snorting bracket 7 of the arm 8. Mountedupon a shelf or support below.

the bracket 7 and upon the insulating slab or plate 2, is a group orseries of open-core transformers 25, one for each transmitter head 14,and from each of said transmitter heads 14 a wire 22 connected as abovedescribed, passes to and connects with the primary coil of one oranother of said opencore transformers. All of said primary coils primarycoils or windings 26, 27, 28, 29,

and. 31 of the transformers 25 are connected in parallel between theconductors 32 and 32" of a local battery 32, or other \sourceOIL-"electric energy, each primary including n the bridge between saidconductors one '"Of the low-resistance, air-cooled transmitters abovedescribed, contained within the several shells or casings 14.

33, 3i, 35, 36, 37 and 38 "indicate the secondary coils of thetransformers 25, which secondaries are arranged in parallel between theconductors 39 and 40, through which the transmitting apparatus isconnected with the wave-generating apparatus of the system. A condenser41, of advisably two microfarad capacity or thereabout, is introducedinto the line or conductor 39, and a like condenser 42 is introducedinto the conductor 40, as indicated.

As the present invention pertains solely to the transmitting apparatusabove described, it is deemed unnecessary to show or describe more ofthe ethereal system as a whole. Details of said complete system are dulyset forth in the earlier applications hereinbefore referred to.

Briefly describing the purpose and action of the present invention, itwill of course be understood that the person desiring to send atelephonic message speaks into the mouthpiece 12, the sound waves beingdirected thereby into the megaphone horn 11, wherein by reason of thesuccessive reflections of the sound waves from side to side of the hornor funnel, and the vibration or amplification of the sound is more orless uncertain, the fact that it takes place is well established, and isrecognized by physicists. From the horn 11 or body of the megaphone, thesound waves pass by the tubes 13 to the diaphragms 17 of the respectivemicro-telephonic transmitters, and thence by the wires or conductors 22to the primary imposed or impressed upon the current flowing through theconductors 39 and 4H. and ultimately upon the ethereal .waves through orby which the signals are transmitted through space.

Byemploying a plurality-of microphonie transmitters, all communicatingwith the.

single mouthpiece and megaphone, I am en abled greatly to intensify orstrengthen the effects produced in the electrical conductors. andfinally impressed upon the ethereal waves. As a consequence, clear andintelligible transmission of speech results.

Seemingly, each separate microphonic transmitter, with its transformer,operates with the same efiiciency when grouped and arranged to receivesound waves from a single mouthpiece and megaphone as when but one suchmicrophonic transmitter is used, and there is consequently impressedupon the electric current the aggregate effect of the severalmicrophonic transmitters. The megaphone serves to deliver to each of thetransmitters a like series of waves, or in other words, effects an evenand perfect distribution thereof to the several transmitters, causingthem to act in perfect harmony and with uniform effect.

The arrangement of the tubes 13 in relation to the megaphone horn 11issuch that the sound waves are projected into and through said tubeswith a minimum of deflection, while the angle of the tubes to the axisof the megaphone is ,such as to separate the microphonic transmittersonly sufficiently to clear one another, and thus to make the pluraltransmitter compact and symmetrical.

The several binding posts 3, 4:, etc., are employed for convenience inmaking the appropriate connections between parts of the apparatus, asusual;

While multiple telephone transmitters have heretofore been used tosecure a more intense energy of transmission the success of such priormultiple devices has been limited by the reduction in the intensity ofaction of the sound waves on the individual diaphragms and by possibleinterference and echoing in the common passage leading from the mouthpiece to the transmitters. I have found that by interposing a megaphonebetween the mouth pieee and the group of transmitters and symmetricallyarranging the latter I can intensify the ef fect of the sound waves oneach transmitter diaphragm and secure true synchronous action withoutany disturbing effects of the character mentioned.

While the specific embodiment of'my invention here illustrated anddescribed has given yery satisfactory results, and is the best formnow-known to me, it. is obvious thatthe general principles ofconstruction and 'operationherein set forth may be incorporated instructures of somewhat different form and ,detail. I therefore do notdesire to be restricted to the specific construction ordetails hereinset forth, but consjemplate such reasonable variations as wouldnaturally be made by skilled mechanicians and electricians in thepractical ap- ,plication and use of my invention. 1 Having thusdescribed my invention, what I claim is 2-- l 1. A telephonictransmitting apparatus "f comprising a mouthpiece; a megaphone or y i fhorn; a head or block joined to the delivery ab :end of the megaphone,and having a plurality of openings through it in the general directionof the axis of the megaphone; tubes applied to of said openings; t terscarried at the free ends of said tubes, one by each tube, substantiallyas described.

2. In a telephonic transmission of sounds, the combination of a centralhead or support bearing a series of substantially identical tubessymmetrically arranged; telephonic transmitters carried one by'each ofsaid tubes; and a megaphone applied to the supporting head the severaltubes,

it I ,;*6opiee or this patent may be obtained for and formingcontmuations and telephonic transmittransmitter for ethereal commontohaving its larger end toward the transmitters whereby a amplifyingchamber is formed. L

3. Incombination with a bracket 09in?- port, a head or block inelectrical connection therewith having a series of symmetrical yarranged passages or openings; a series pt tubes each communicating withone other of said openings; a series'of telephonic transmitters carriedby the respective tubes, one by each; a megaphone, the delivery end; ofwhich is common to the several tubes,

and

symmetrically arranged with reference thereto; and phone. i

4. A telephonic transmitting apparatus comprising amouth or a gregateefiect.

g whereof I have signed my In testimony name'to this specification inthe presence of two subscribing witnesses.

' t FREDERICK HOYEB MILLENER. I

- "Witnesses:

F. J. GRIFFIN,

R. H. 'BALLANTINE,

five cent: each, by addreuln'g the Commissioner 0! letelte, Washington,D. 0."

a ,mouthpiece for said mega-

